During his career at NASA, Charles Bolden Jr. had his eye on deep space and his feet on the ground.

This week Bolden, a retired Marine Corps major general, four-time astronaut and former NASA administrator, received the 2017 Nierenberg Prize for Science in the Public Interest from Scripps Institution of Oceanography.

“We all know that to understand this planet better, we must understand what else is out there in our solar system and our universe,” he said during the award ceremony at the Scripps campus in La Jolla Tuesday.

The prize is bestowed in honor of William Nierenberg, a physicist on the Manhattan Project and director of Scripps Oceanography from 1965 to 1986. Following his death in 2000, family members established the prize to honor people who make “big contributions” to research and discovery, “connecting science to all of us,” his son, Nicolas Nierenberg, said Tuesday.

As the 2017 recipient, Bolden finds himself in the company of scientists including human genome pioneer Craig Venter and primatologist Jane Goodall, as well as media icons such as newscaster Walter Cronkite and filmmaker James Cameron.

“As NASA administrator, Gen. Bolden saw his role to be the head of space for the Earth, an ambassador for science, technology and appreciation for the natural world,” Nierenberg’s daughter, Victoria Tschinkel, said in address at the event. “He is a visionary, inspiring all of us to think about the wonders that are out there, that we can feel, measure and maybe even touch.”

Bolden, 71, flew more than 100 combat missions over the tree-line in Vietnam, and four space shuttle voyages hundreds of miles above the Earth. He piloted the Space Shuttle Discovery on its mission to deploy the Hubble Space Telescope, and commanded the ATLAS-1 mission dedicated to Earth science. Gazing down at the swirling ocean and arc of the atmosphere, he saw all that was at stake in the quest to understand Earth and its celestial neighbors.

“Having been blessed to see our planet from space, I can attest that from up there you don’t see borders,” he said. “You see a place seemingly at peace, in tranquility and one beautiful planet. You see one ocean, only one. We’re a water planet. You realize pretty quickly that what happens in one part of the ocean affects the others.”

Serving as NASA director from 2009 to 2017, the first African-American to hold that post, Bolden presided over the landing of the Mars Curiosity Rover in 2012 and the Juno spacecraft’s entry into Jupiter’s orbit in 2016, as well as preparation for the launch of the James Webb Space Telescope, which he expects will “dwarf what we learned about the universe by the Hubble.”

In a lunch meeting with UC San Diego students before the ceremony, Bolden described the astonishment and elation of space flight.

Hours of apprehension prior to launch are followed by the explosive takeoff and eight minutes of feeling “like you have gorillas sitting on your chest, and then you’re floating at 12,500 miles per hour,” he said. “You can see the curvature of the Earth. You see the atmosphere, the thin blue line. And it’s just breathtaking. You’re not quite prepared for the beauty of it.”

In some ways Bolden’s career followed a similar trajectory, from nerve-racking struggle to international success. Born in 1946 in Columbia, S.C., during the era of segregation, he attended what he called “separate and unequal” schools that didn’t offer advanced math or science. But his mother, a school librarian, and father, a teacher and football coach, taught him to reach beyond those limitations.

His seventh-grade math and science teachers stoked his interest in those fields, introducing him to mathematical “set theory” and requiring him to enter science competitions. He fell in love with science fairs, and developed a fascination with the U.S. Naval Academy after watching a film on Annapolis.

“I loved the uniforms,” he said. “The esprit de corps was really exciting.”

In 1964, Bolden enrolled in the academy, and promptly discovered that he hated it. The grueling introduction known as “plebe summer” was far harder than expected, and he was one of only seven black students in a class of 1,400 students. The environment was hostile, he said, and he confided to his parents that he wanted to quit. Each week his dad urged him to stick it out for “one more week,” and 52 weeks later he found his stride. That year and the next one, he was elected president of his class at the Academy.

Bolden graduated in 1968 with a degree in electrical science and enlisted as a Marine infantry officer, but discovered that he didn’t like crawling in the mud. At his wife’s urging — and against his inclinations — he enrolled in flight school, and found his passion. From the first time he flew a plane, he adored the feeling of freedom, the stunning views, and exacting precision. He served in Vietnam from 1972 to 1973, flying move than 100 combat missions in an A-6 Intruder.

He later became a test pilot when astronaut Ron McNair persuaded him to apply for the space program, overcoming Bolden’s doubts about his prospects by insisting that “you won’t know unless you ask.” In 1980, he was accepted into the program, and between 1986 and 1994, he made four shuttle flights with NASA. In 2009, under President Barack Obama, he took charge of the agency, convinced that space exploration could benefit life on Earth.

Technologies used to power satellites can help produce cleaner energy on Earth, he said, and systems to recycle water for astronauts could help preserve terrestrial water resources. A device developed to record signals in Martian soil has proven useful to detect survivors in the rubble of earthquakes, he said.

“I am here this evening to tell you that I believe space exploration is one of the most important tools this generation will use to bring about the better future that you deserve – a more peaceful future; a greener future,” Bolden said.